Mutations in mice that influence natural killer (NK) cell activity

Obligatory role of B cells and adherent accessory cells in the transfer of a defect in morphine-mediated antinociception in C57BL/6J-bg/bg (beige-J) mice

C57BL/6J-bg/bg (beige-J) mice have a blunted antinociceptive response to intracerebroventricularly (i.c.v.) injected morphine in the tail-flick test. Beige-J mice are also immunologically defective and exhibit the pathology of Chediak-Higashi syndrome (CHS). We transferred by i.v. injection 2 x 10(7) mononuclear spleen cells, devoid of PMNs, obtained from beige-J mice to normal C57BL/6J-bg/+ littermates that do not exhibit CHS or a blunted antinociceptive response to morphine. After 8 days, the normal littermates demonstrated significant (P less than 0.05) reduction in their analgesic responsiveness to morphine. This phenomenon was found to require B-cells and adherent cells in the adoptively transferred spleen cells. B-cells that had been purified by panning on anti-Ig-coated plates were sufficient to transfer the analgesic defect unless adherent cells were removed prior to immunocytoadherence. T-cells, in the presence or absence of adherent cells, failed to transfer the decreased sensitivity to morphine. These results demonstrate a novel neuroimmune interaction whereby B-lymphocytes and adherent cells, or a substance derived from them, are able to affect the antinociceptive action of morphine.

The C57BL/6 nude, beige mouse: a model of combined T cell and NK effector cell immunodeficiency

This article describes the construction and establishment of a double congenic nude, beige C57BL/6 (B6 nu, bg) mouse strain. The mice do not show higher fragility than C57BL/6 nude mice and the double congenic strain can be maintained under conventional mouse housing conditions. Although the B6 nu, bg display a very low natural killer activity which cannot be enhanced by an interferon inducer (poly(I-C], they lack responsiveness to a T cell mitogen (concanavalin A); and they also show extremely low responsiveness to a B cell mitogen (0128: B12 Escherichia coli lipopolysaccharide) probably as a result of combined effects of the beige and nude genes in the C57BL/6 genetic context.

Mast-cell-deficient W/Wv mice exhibit a decreased rate of tumor angiogenesis

The role of host mast cells in tumor-associated angiogenesis was investigated by comparing the angiogenic response of genetically mast-cell-deficient W/Wv mice and mast-cell-sufficient +/+ littermate mice to s.c. growing B16-BL6 tumors. The angiogenic response was found to be slower and initially less intense in W/Wv mice than in +/+ mice. Fewer W/Wv mice than +/+ mice developed spontaneous lung metastases and W/Wv mice exhibited fewer lung metastases per mouse. Bone-marrow repair of the mast-cell deficiency restored the angiogenic response of W/Wv mice and also restored the incidence of hematogenous metastases to approach that of +/+ mice. Differences in lymphatic metastasis were not detected between W/Wv and +/+ mice. These results demonstrate a role for mast cells in vivo during tumor angiogenesis, and suggest a role also for host mast cells in hematogenous metastasis.

The autoimmune mouse MRL/Mp-lpr/lpr contains cells with spontaneous cytotoxic activity against target cells bearing self-determinants

Spontaneously cytotoxic cells possessing specificity and having a complex pattern of reactivity directed at least partly against self-determinants develop by the age of 10 weeks in the autoimmune mouse strain MRL/Mp-lpr/lpr (MRL-lpr) and by the age of 6 months in C57BL/6-lprl/lpr. Similar effector cells do not develop in either MRL/Mp-+/+(MRL-+/+) or normal C57BL/6 mice up to 6 months old. Freshly prepared suspensions of both lymph node and bone marrow cells from individual MRL-lpr mice could kill Con A- or LPS-induced blast cells and fresh thymocytes from MRL-+/+ and other mouse strains with strong preference for strains carrying (self)-H-2k determinants in a 4-hr51Cr release assay. These results imply that self-reactive cells are generated as part of the lpr gene defect.

Host genotype, pathogenic challenge and periodontal bone loss in the mouse

Periodontal bone loss was induced in mice of different genotypes by oral inoculation with Actinomyces viscosus. Relatively high bone loss occurred in the mutant X-linked immune deficiency, implicating the humoral immune system. Maximum bone loss was always associated with inoculations of 1.6 x 10(7) colony forming units (c.f.u.), while inoculations of 1.6 x 10(6) or 1.6 x 10(9) c.f.u. resulted in bone loss little different from that in uninoculated controls. This 1000-fold range in inoculum size was not reflected in the number of A. viscosus organisms recovered from the molar teeth at the end of the experimental period, suggesting that differences in bone loss stemmed from the host response to the initial inoculum.

Altered natural killer and natural cytotoxic cellular activities in lpr mice

Three strains of mice bearing the autosomal recessive lpr gene (MRL, C57BL/6, and C3H) that had spontaneously developed a lupus-like disease were studied sequentially for functional natural killer (NK) and natural cytotoxic (NC) cell activity. Natural killing was impaired in spleen and bone marrow cells from all the lpr strains, as well as from the congenic strain MRL--+/+, which develops a late onset lupus-like disease. The NK cell activity was found to be depleted as early as 2 months of age in all lpr strains, and decreased further with age. NK activity was augmentable by Poly I:C and interleukin 2 (IL-2), suggesting that the residual cells can respond to NK modulators. In contrast with NK cell activity, NC activity was not decreased in lpr mice but could be augmented by IL-3-rich supernatants. The spontaneous decrease in NK cell activity was associated with an increased autologous plaque-forming cell (APFC) response to bromelin-treated mouse red blood cells, which is produced primarily by B cells possessing the Ly-1 phenotype (Lyt-1+ B). When NK cell activity was increased by exogenous administration of Poly I:C, the APFC response diminished. Treatment of spleen cells with anti-asialo GM1 prior to Poly I:C treatment resulted in a decreased NK response but increased both APFC and Lyt-1+ B cells. The possible regulation of autoreactivity by NK cells is discussed.

Genetic resistance to murine cryptococcosis: the beige mutation (Chédiak-Higashi syndrome) in mice

The influence of the bgJ and bg2J mutations on the susceptibility of mice to experimental cryptococcosis was studied in inbred mice of the C57BL/6J and C3H/HeJ strains. Although infected animals with the bg/bg genotype had a significantly shorter lifespan than bg/+ or +/+ animals, C3H/He beige-2J mice were less susceptible than C57BL/6 beige-J mice when compared with nonbeige mice of similar background. On days 18 and 19 after infection, quantitation of cryptococci in the brain, liver, and spleen revealed that the overall burden of organisms in infected C57BL/6 beige-J mice was in excess of one log unit above that found in the brain, liver, and spleen of infected C57BL/6 +/+ mice. At that time, C57BL/6 beige-J mice showed a 53% increase in mean brain weight, a 67.8% decrease in mean liver weight, and a 58.6% decrease in mean spleen weight, when compared with uninfected animals of the same age and genetical lineage. The corresponding figures for C57BL/6 +/+ mice were a 32% increase in mean brain weight, a 41.4% decrease in mean liver weight, and a 23.4% decrease in mean spleen weight. From these data, it is concluded that the beige mutation in mice is associated with increased susceptibility to cryptococcosis, the accrued susceptibility of the beige mutant is related to more rapid changes in the weight profile of the target organs as well as to a higher rate of growth or decreased clearance of Cryptococcus neoformans or both, and other autosomal genes are likely to be involved in the genetic control of susceptibility to murine cryptococcosis.

Immune characteristics of the beige-nude mouse. A model for studying immune surveillance

Double immunodeficient mice, homozygous for both the beige and the nude genes, were developed on C57BL/6N-beige and N:NIH(S)-nude background through five steps of mating. The animals were healthy and had a life span comparable to that of regular nude mice. Beige and regular nude mice showed a significant difference in natural killer (NK) activity, with mean +/- SE values of 6 +/- 1.0% and 25 +/- 2.8%, respectively. The response to the T-cell mitogens phytohaemagglutinin and concanavalin A was similar in beige and NIH mice of the same genotypes for the nude genes. Both groups of nu/nu mice also showed some response in these assays, as well as in the plaque-forming cell assay, indicating that nude mice are not completely devoid of functional T or T-like cells. The nude genes were found to increase the response to the B-cell mitogen lipopolysaccharide in both the beige and NIH animals, whereas the response was reduced in mice of the beige genotypes. The viable, low NK beige-nude mice here reported on may be a valuable tool for studying factors involved in host defence against tumours. Interestingly, no spontaneous tumours have so far been observed in such mice.

The cooperative effect of the satin and beige mutations in the suppression of NK and CTL activities in mice

The functional activity of natural killer (NK) cells has been found to be modulated by several point mutations associated with coat color. The most commonly studied gene, beige (Bg), has been found to block a postrecognition event in the lytic cycle. Four other coat color mutations in the mouse (satin, leaden, fuzzy, pale ears) were studied for their effect on NK cell function, and only one, satin (Sa), was found to be suppressive. When both the Sa and Bg mutations were present in the same animal, their effects were synergistic in the suppression of NK levels. Normal numbers of NK cells were present in these double mutants, as determined by the frequency of IgG2b binding cells and by antiasialo GM1 staining. The ability of Sa/Bg NK cells to recognize and bind targets suggests that the defect is localized in the postbinding cytolytic pathway. These genes were not specific for NK cells and also suppressed alloimmune cytolytic T lymphocyte function. Since Sa/Bg mice are much more suppressed in NK function than Bg mice, we suggest that this double mutant may be a better model for NK deficiency in vivo.

Genetic control of murine antibody-dependent cell-mediated cytotoxicity. Partial identity with the genetic control of NK activity

We have observed that the intensity of the direct antibody-dependent cell-mediated cytotoxicity (ADCC) response after an inoculation of foreign tumour cells varies with the strain of mice studied. The inoculation of a human lymphoblastoid cell-line into CBA/J, BALB/c, or DBA/2 mice gives rise to a good cytotoxic response by the host K cells armed with specific antibodies. In contrast, A/J, B10.A, C57BL/6 and B10.S mice respond poorly under the same conditions. The high response is dominant in F1 hybrids between high and low responders and is also expressed among F2 backcrosses with the H-2 phenotype of low responders, suggesting that non-H-2 genes are also implicated in the regulation of ADCC. The genetic control is not exerted at the level of antibody secretion but at that of K-cell activity, since sera from high or low responders are equally effective in arming an ADCC reaction, whereas K cells from low-responder strains are less efficient than those from high-responder strains. The natural killer (NK) activity of the same strains has been screened. The results show a good correlation with some high- and low-responder strains, such as CBA and DBA/2 or A/J and SJL, respectively, but not with C57BL/6, B10.S or B10.A strains. Thus, in addition to common genes controlling both lytic functions, there are specific genetic factors influencing the balance between NK and K cells. These findings confirm the general view that NK and K cells represent only partially identical subsets.